Man page - libwget-io(3)
Packages contains this manual
- libwget-console(3)
- libwget-utils(3)
- libwget-error(3)
- libwget-hash(3)
- libwget-net(3)
- libwget-stringmap(3)
- libwget-xml(3)
- libwget-dns(3)
- libwget-robots(3)
- libwget-base64(3)
- libwget-io(3)
- libwget-parse_sitemap(3)
- libwget-dns-caching(3)
- libwget-printf(3)
- libwget-bitmap(3)
- libwget-vector(3)
- libwget-ip(3)
- libwget-hashmap(3)
- libwget-mem(3)
- libwget-thread(3)
- libwget-parse_atom(3)
- libwget-xalloc(3)
- libwget-random(3)
- libwget-list(3)
apt-get install wget2-dev
Manual
libwget-io
NAMESYNOPSIS
Functions
Detailed Description
Function Documentation
ssize_t wget_fdgetline (char ** buf, size_t * bufsize, int fd)
ssize_t wget_getline (char ** buf, size_t * bufsize, FILE * fp)
int wget_ready_2_transfer (int fd, int timeout, int mode)
int wget_ready_2_read (int fd, int timeout)
int wget_ready_2_write (int fd, int timeout)
char * wget_read_file (const char * fname, size_t * size)
int wget_update_file (const char * fname, wget_update_load_fn * load_func,wget_update_save_fn * save_func, void * context)
int wget_truncate (const char * path, off_t length)
Author
NAME
libwget-io - I/O helper routines
SYNOPSIS
Functions
ssize_t
wget_fdgetline
(char **buf, size_t *bufsize, int fd)
ssize_t
wget_getline
(char **buf, size_t *bufsize,
FILE *fp)
int
wget_ready_2_transfer
(int fd, int timeout, int
mode)
int
wget_ready_2_read
(int fd, int timeout)
int
wget_ready_2_write
(int fd, int timeout)
char *
wget_read_file
(const char *fname, size_t
*size)
int
wget_update_file
(const char *fname,
wget_update_load_fn *load_func, wget_update_save_fn
*save_func, void *context)
int
wget_truncate
(const char *path, off_t
length)
Detailed Description
Some general I/O helper functions that could be handy for developers.
Function Documentation
ssize_t wget_fdgetline (char ** buf, size_t * bufsize, int fd)
Parameters
buf
Pointer to a pointer
that will be set up by the function to point to the read
line
bufsize
Pointer to a variable where the length of the
read line will be put
fd
File descriptor for an open file
Returns
The length of the last line read or a WGET_E_* error code (< 0)
Behaves identically as wget_getline() , but uses a file descriptor instead of a stream.
ssize_t wget_getline (char ** buf, size_t * bufsize, FILE * fp)
Parameters
buf
Pointer to a pointer
that will be set up by the function to point to the read
line
bufsize
Pointer to a variable where the length of the
read line will be put
fp
Pointer to an open file’s stream handle
(
FILE *
)
Returns
The length of the last line read or a WGET_E_* error code (< 0)
This function will read a line from the open file handle fp . This function reads input characters until either a newline character ( \\n ) is found or EOF is reached. A block of memory large enough to hold the read line will be implicitly allocated by the function, and its address placed at the pointer pointed to by buf . The length of the aforementioned memory block will be stored in the variable pointed at by bufsize .
The caller is not expected to allocate memory as that will be automatically done by wget_getline() , but it is responsibility of the caller free the memory allocated by a previous invocation of this function. The caller is also responsible for opening and closing the file to read from.
Subsequent calls to wget_getline() that use the same block of memory allocated by previous calls (that is, the caller did not free the buffer returned by a previous call to wget_getline() ) will try to reuse as much as possible from the available memory. The block of memory allocated by wget_getline() may be larger than the length of the line read, and might even contain additional lines in it. When wget_getline() returns, the contents of the buffer (pointed at by buf ) are guaranteed to start with the first character of the last line read, and such line is also guaranteed to end with a NULL termination character ( \0 ). The length of the last read line will be returned by wget_getline() , whereas the actual length of the buffer will be placed in the variable pointed at by bufsize . The newline character ( \\n ) will not be included in the last read line.
int wget_ready_2_transfer (int fd, int timeout, int mode)
Parameters
fd
File descriptor to
wait for
timeout
Max. duration in milliseconds to wait
mode
Either
WGET_IO_WRITABLE
or
WGET_IO_READABLE
Returns
-1 on error
0 on timeout - the file descriptor is not ready for reading
or writing
>0 The file descriptor is ready for reading or writing.
Check for the bitwise or of
WGET_IO_WRITABLE
and
WGET_IO_READABLE
.
Wait for a file descriptor to become ready to read or write.
A
timeout
value of 0 means the function returns
immediately.
A
timeout
value of -1 means infinite timeout.
int wget_ready_2_read (int fd, int timeout)
Parameters
fd
File descriptor to
wait for
timeout
Max. duration in milliseconds to wait
Returns
-1 on error
0 on timeout - the file descriptor is not ready for reading
1 on success - the file descriptor is ready for reading
Wait for a file descriptor to become ready to read.
A
timeout
value of 0 means the function returns
immediately.
A
timeout
value of -1 means infinite timeout.
int wget_ready_2_write (int fd, int timeout)
Parameters
fd
File descriptor to
wait for
timeout
Max. duration in milliseconds to wait
Returns
-1 on error
0 on timeout - the file descriptor is not ready for writing
1 on success - the file descriptor is ready for writing
Wait for a file descriptor to become ready to write.
A
timeout
value of 0 means the function returns
immediately.
A
timeout
value of -1 means infinite timeout.
char * wget_read_file (const char * fname, size_t * size)
Parameters
fname
The name of the
file to read from, or a dash (
-
) to read from STDIN
size
Pointer to a variable where the length of the
contents read will be stored
Returns
Pointer to the read data, as a NULL-terminated C string
Reads the content of a file, or from STDIN. When reading from STDIN, the behavior is the same as for regular files: input is read until an EOF character is found.
Memory will be accordingly allocated by wget_read_file() and a pointer to it returned when the read finishes, but the caller is responsible for freeing that memory. The length of the allocated block of memory, which is guaranteed to be the same as the length of the data read, will be placed in the variable pointed at by size .
The read data is guaranteed to be appended a NUL termination character ( \0 ).
int wget_update_file (const char * fname, wget_update_load_fn * load_func,wget_update_save_fn * save_func, void * context)
Parameters
fname
File name to
update
load_func
Pointer to the loader function
save_func
Pointer to the saver function
context
Context data
Returns
0 on success, or WGET_E_* on error
This function
updates the file named
fname
atomically. It lets
two caller-provided functions do the actual updating. A lock
file is created first under
/tmp
to ensure
exclusive access to the file. Other processes attempting to
call
wget_update_file()
with the same
fname
parameter will block until the current calling process has
finished (that is, until
wget_update_file()
has
returned).
Then, the file is opened with read access first, and the
load_func
function is called. When it returns, the
file is closed and opened again with write access, and the
save_func
function is called. Both callback
functions are passed the context data
context
, and
a stream descriptor for the file. If either function
load_func
or
save_func
returns a non-zero
value,
wget_update_file()
closes the file and returns
-1, performing no further actions.
int wget_truncate (const char * path, off_t length)
Parameters
path
File path
length
New file size
Returns
0 on success, or -1 on error
Set path to a size of exactly length bytes.
If the file was previously larger, the extra data is lost. If the file was previously shorter, extra zero bytes are added.
On POSIX, this is a wrapper around ftruncate() (see ’man ftruncate’ for details).
Author
Generated automatically by Doxygen for wget2 from the source code.